Hundreds of people could have been contaminated by the nerve agent that poisoned a Russian double agent in Salisbury, officials have confirmed, as locals questioned last night why they were not warned sooner.

Hundreds of people could have been contaminated by the nerve agent that poisoned a Russian double agent in Salisbury, officials have confirmed, as locals questioned last night why they were not warned sooner.

A week after Sergei Skripal and his daughter Yulia were left in a critical condition following an attack in the English city, residents were advised to take action to protect themselves.

Anyone who visited the same pub or restaurant as the pair last Sunday was told to wash their clothes immediately and clean all jewellery, mobile phones, spectacles and other items with antiseptic wipes.

Theresa May will today lead a meeting of the National Security Council, attended by the heads of all three intelligence agencies, after which she is expected to formally link Russia to the Salisbury poisonings.

Scientists at Porton Down, the UK government's chemical warfare laboratory, are understood to have been carrying out final tests overnight that will prove beyond reasonable doubt that the nerve agent used in the attacks was made in Russia.

Mrs May is then expected to announce fresh sanctions against Russians close to Vladimir Putin, as well as the expulsion of some Russian diplomats from the UK.

Tables and chairs remain unused inside the closed pub which Sergei Skripal and his daughter Yulia visited before they were found poisoned. REUTERS

As the police and military operation continued in Salisbury, staff at the Zizzi restaurant, where the couple dined shortly before falling ill, were told to destroy any clothes they had been wearing at the time and also visit their doctor for a health check.

There were claims last night that the nerve agent had been found all over the pair's table.

Drinkers at the popular Mill pub in the city were also urged to take similar steps if they were there between Sunday lunchtime and Monday night, when the venue was eventually sealed by police.

Traces of the nerve agent - which has been identified but that officials have refused to name - have also been found at the pub, it is believed.

Last night there was growing anger among Salisbury residents over the delay in passing on information to the public.

Maureen Jones (73) who has lived in Salisbury her entire life, said: "I can't understand why it has taken a week for them to tell people."

Dan Munday said: "Enough of this cloak and dagger stuff, let the public know what's going on. It is our city after all."

Another resident who was in the Mill pub at about the same time as Col Skripal and his daughter said he was outraged that he was only now being told to take preventive measures.

He said: "I am not reassured because I do not know all the facts. What are the long-term effects?"

While health officials insisted the risk to the public was minimal, members of the military, wearing chemical protection suits, continued to seal off parts of the city.

Just minutes after holding a press conference intended to reassure the public, scores of military personnel, police officers and paramedics descended on Bourne Hill police station and offices in the city.

Two military tents were set up and dozens of army personnel donned protective suits as they moved a series of vehicles from the car park.

It is thought the vehicles could have been used by police officers who attended the scene of the attack last Sunday.

Det Sgt Nick Bailey, one of the first responders, remains in a serious condition in hospital, although he can sit up and talk.

Philip Ingram, a former intelligence and security officer who has studied chemical warfare, said all the indications pointed towards a liquid nerve agent similar to the one used to kill North Korean leader Kim Jong-un's half brother last year.

Mr Ingram said: "The fact that traces have been found at multiple locations suggests this is almost certainly a thickened liquid that would have a very persistent effect.